Biological monitoring in the occupational setting--relationship to cadmium exposure

Statutory health surveillance of occupational exposure to cadmium exists in most Western countries. For biological monitoring, both indicators of internal dose and indicators of effect are available. Cadmium in urine is an indicator of chronic exposure and essentially reflects the body burden under low-exposure conditions and in the absence of renal damage. Whole blood cadmium is primarily a useful indicator for use in evaluations of recent exposures. Biological threshold limit values for cadmium in urine and blood are based on the correlation of biological levels with thresholds for renal dysfunction. The use of markers of high and low molecular weight proteinuria should be integrated into the health surveillance of cadmium-exposed workers. Priority should be given to the determination of albumin and of proteins such as beta 2-microglobulin, retinol-binding protein and alpha 1-microglobulin. Interpretation of biological monitoring data in terms of the threshold values requires a programme of periodic biological, medical and environmental monitoring.